How To Test Your Water


Bacteriological/ Microbiological and Chemical sampling is a very important water quality monitoring device. Typical testing suites are listed below.

If you have a specific problem / concern please provide as much information as possible to our staff who will endeavour to assist you in identifying the most suitable tests to perform. 


How to take water samples:

It is of paramount importance that you are careful not to contaminate the sample in any way as everyone has a large number of bacteria on their hands all the time. Samples should ideally be taken from the main cold water drinking tap closest to the source / well.


Materials Required

  • 2 Sterile Water bottles (available from ALS)
  • Cotton wool
  • Isopropanol (70%) or Methylated Spirits /Alcohol Wipes or equivalent



  1. Remove any anti-splash devices from tap and wipe around the spout with clean cotton wool, to remove all visible signs of contamination.
  2. Turn on the tap and flush to waste steadily, not violently, for at least two minutes. This helps to ensure the pipes are cleared of any stagnant water and therefore that the water tested is representative of the source.
  3. Turn off the tap and sterilise it, using cotton wool and 70% isopropanol or with an alcohol wipe or equivalent.
  4. Flush the tap gently for two minutes – this will remove any excess isopropanol (if used). DO NOT touch any part of the tap again. DO NOT alter the flow rate until you have completed sampling.
  5. With the tap still running remove cap from the bottle (and thus break the sterility seal) – keep the cap pointing downwards and do not put it down. DO NOT open the bottle until the moment it is required for filling. DO NOT touch the inside of the cap or the top of the bottle and DO NOT let the bottle touch the tap.
  6. Hold the bottle at the bottom, at a slight angle under the stream of water, and fill to the neck, avoiding splashing.

DO NOT allow the bottle to overflow, as it contains sodium thiosulphate. Replace the cap immediately making sure that it is properly sealed.


Storage and Transport to the Laboratory

Complete the Analysis Request Form below and return samples to the laboratory as soon as possible – ideally within 2-3 hours of sampling. Please bring your water samples to one of the ALS locations around Ireland listed below:

Clonmel: ALS, Carrigeen Business Park, Clonmel, Co. Tipperary, E91 PF63.


Samples can be accepted here from 9:00am to 5:30pm Monday to Friday.

Portlaoise: ALS, Lismard Industrial Estate, Timahoe Road, Portlaoise, R32 EK12.

Samples can be accepted here up until 1:00pm Monday – Friday.

Cork: ALS, 33 Eastgate Drive, Little Island, Cork, T45 C446.

Samples can be accepted here between 8:00am and 9:00am from Tuesday to Friday for same day testing.

Portadown: ALS, Unit 38 & 39 CIDO Business Complex, Carn Drive, Portadown, Co Armagh, BT63 5WH.

Samples can be accepted up to 1:45pm Monday to Friday.


Posting Samples:

Samples may be posted providing they arrive in the laboratory within 24 hours of taking the samples to ensure the integrity of the sample.

Please post your water samples to:
ALS, Carrigeen Business Park, Clonmel, Co. Tipperary, E91 PF63.

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